Add to installed apps

INSTALLED_APPS = (
    ...
    'formfield',
    ...
)

Example

from django.db import models
from django import forms

from formfield import ModelFormField

class PersonMetaForm(forms.Form):
    age = forms.IntegerField()
    sex = forms.ChoiceField(choices=((1, 'male'), (2, 'female')), required=False)


class Person(models.Model):
    name = CharField(max_length=200)

    meta_info = ModelFormField(form=PersonMetaForm)

Which will result in something like this (using the admin)

The ModelFormField is automatically set to null=True, blank=True, this is because validation is done on the inner form. As a result you will see something like the following if we hit save on the change form:

If we supply the change for valid data you should get a python dictionary when retrieving the data:

>>> person = Person.objects.get(pk=1)
>>> person.meta_info
{u'age': 12, u'sex': u'1'}

The form is the only thing forcing valid input, behind the scenes the data is being serialized into json. Therefore on the python level we can supply meta_info any valid json::

>>> from sample_app.models import Person
>>> data = {'some': 'thing', 'is': 'wrong', 'here': 'help!'}
>>> p = Person.objects.create(name="Joan", meta_info=data)
>>> p.meta_info
{'is': 'wrong', 'some': 'thing', 'here': 'help!'}